I think what your argument does, actually, is strengthen Sander’s assertions, not weaken them. The point you seem to be missing is that he is leading by example. This is the thing people see in real time. People aren’t merely responding emotionally to the idea of campaign finance reform, they are reforming in real time, by example as well. The people are volunteering to reform campaign finance. While the Clintons and their supporters continue to attempt to distort and deceive with every movement of their jaws, the people behind Sanders respond by just donating more and more small donations, and that is more powerful than all the words.
He has repeatedly said it is going to take the involvement of 10's of millions of people to make the changes that have to be made. This fundraising is like practice for the big time. The Clinton’s are betting that all this momentum helps her candidacy because they assume it is fueling the Democratic Party. It’s not even about Sanders and the Democratic Party any more. It’s not so simple, It’s bigger than than the Democratic Party. It’s bigger than the TV that just hopes by ignoring it that it will go away, and it’s bigger than money. If untrustworthy, bought and paid for treachery and deceit beholden to the corporate class wins this election, if you think the Two-Party stalemate is bad, wait till you see what 10's of millions of volunteer citizens can do.